WO 94/27049 A1 describes a double-flow multiphase screw spindle machine for the delivery of a multiphase mixture. As the feed elements, two contactlessly intermeshing, contrarotating feed screw pairs are provided, respectively comprising a right-hand feed screw and a left-hand feed screw. The interlocking feed screws form, together with the housing enclosing them, individually closed-off feed chambers. Upon rotation via a drive shaft, these chambers move continuously and parallel to the shafts from the suction side to the pressure side. The suction side is here arranged centrically, with the pressure chamber surrounding the feed spindles. In the pressure chamber, devices for separating the respective liquid phase from the gas phase of the medium flow leaving the feed screw are provided. A part-quantity of the separated liquid phase is led back to the suction chamber via a short-circuit line.
EP 183 380 A1 describes a double-flow screw spindle pump having an inlet chamber disposed on the front of the feed screw pairs. The medium to be pumped is moved into convergence by the two feed screw pairs and is discharged from a centrally disposed outlet. A similarly constructed screw spindle pump is known from GB 2,227,057 A1. Condensers for vaporized fluid are provided within the housing in order to provide an adequate liquid supply.
U.S. Pat. No. 4,995,797 describes a single-flow screw spindle pump having a pressure-controlled return flow of a separated liquid component. The separator is disposed on the pressure side of the pump.